Forum rules
For new users: this forum is moderated. Your first post will appear only after it has been reviewed by a moderator, so it will not show up immediately.This is necessary to avoid this forum being flooded by spam.

HHbomb wrote:RTX cards are really fantastic, but what about rendered image quality ? Same as before ?

Yes - as mentioned in the FAQ quality is the same. The worst case scenario is that for scenes that don't benefit from RT Cores (volumes and non-mesh heavy scenes, low complexity mesh scenes), they render at least the same OB as before (e.g. RTX off). The scene in this RTX benchmark is the first one we encountered (basically by accident during testing) that always hits around 2-3x the speed, most were half that.

To be clear, and to make sure we set expectations correctly, RTX boost IS NOT going to get you a 2.5x+ increase in path tracing speed (or 5x+ the info kernel speed) for every scene. Today, it is consistently delivering a little less than half this boost for many scenes we've tested (e.g. 1.2x+ in PT and 2x in Info kernel). On the plus side, we never got anywhere near a 3x PT/DL speed boost in Octane just a few months ago, so with further tuning we hope to see if we can get more consistent high speed boosts across more and more scenes...

The purpose of this benchmark today is to provide a current WIP snapshot of the scene dependent min/max range for rendering speed on RTX GPUs. The min/max range starts with normal OB (i.e. RTX off= approx OB3/OB4 speed) as the minimum OB speed you should count on for all scenes, and 'OBX' as our maximum possible OB speed (with RTX on) as measured in best case scenarios like in this benchmark scene, which can fully benefit from RT Core HW.

Our work going forward, beyond engine tuning, is to provide more RT Core optimization tools and features that make it easier to leverage full 'OBX' speed. One example, the new 2019.1 vertex displacement system can fully use RT Cores, but old (pre-2019.1) displacement nodes do not (and will be relatively much slower on RTX). Down the line, we are looking at a scene optimizer (i.e. converting old displacement nodes to the new system mentioned before) or even a completely new kernel that could be added alongside current PT/DF/PMC kernels, but with minor (possibly automated) workflow changes is designed for 'maximum OBX' speed on RT Cores (more on that at GTC).

Last edited by Goldorak on Tue Feb 19, 2019 10:49 pm, edited 2 times in total.

I tried both 417.71 and 417.35 and neither one is utilizing RTX. Anything else I can try?

We have contacted NVidia for further feedback about your setup and it seems that RTX support for RTX 2070 might have come in driver 418.x series, which is currently breaking other Octane functionality but which should be fixed sometime this week.

mojave wrote:We have contacted NVidia for further feedback about your setup and it seems that RTX support for RTX 2070 might have come in driver 418.x series, which is currently breaking other Octane functionality but which should be fixed sometime this week.

Thanks so much for checking! I'll try again with the next version when it's ready.

Goldorak wrote:To be clear, and to make sure we set expectations correctly, RTX boost IS NOT going to get you a 2.5x+ increase in path tracing speed (or 5x+ the info kernel speed) for every scene. Today, it is consistently delivering a little less than half this boost for many scenes we've tested (e.g. 1.2x+ in PT and 2x in Info kernel).

I think it is more fair to say that it is 1/8 the boost instead of half (20% gain instead of 150% gain).

We got some great results with OctaneBench 2019 preview on a quad RTX 2080 system, but when I tried to run the same cards in two NVLink pairs we got an error. Perhaps the RTX-On codepath isn't yet supporting NVLink? I'm including a screenshot of the error, with some additional details, but if you want more info or for me to try anything specific out please let me know.

You may note that the error specifically indicates problems with GPUs 1 and 3. Those are the "secondary" cards in each NVLink pair - GPUs 2 and 4 were where monitors were plugged in, and running OB 2019 with only those GPUs selected allowed it to complete, but it only used two of the four GPUs and so performance was of course much lower than with all four cards.

Note this is an experimental build and some features may not be handled as they are in production builds. We have got some reports of this benchmark running successfully with NVlink enabled for two cards but not with the exact same setup as you do so we'll try to reproduce it to make sure this is fix in the next builds.